addon-sdk/source/lib/sdk/system/unload.js@6474c204b198 (annotated)
addon-sdk/source/lib/sdk/system/unload.js
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 2 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 3 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 4 | |
| michael@0 | 5 | // Parts of this module were taken from narwhal: |
| michael@0 | 6 | // |
| michael@0 | 7 | // http://narwhaljs.org |
| michael@0 | 8 | |
| michael@0 | 9 | module.metadata = { |
| michael@0 | 10 | "stability": "experimental" |
| michael@0 | 11 | }; |
| michael@0 | 12 | |
| michael@0 | 13 | const { on, off } = require('./events'); |
| michael@0 | 14 | const unloadSubject = require('@loader/unload'); |
| michael@0 | 15 | |
| michael@0 | 16 | const observers = []; |
| michael@0 | 17 | const unloaders = []; |
| michael@0 | 18 | |
| michael@0 | 19 | var when = exports.when = function when(observer) { |
| michael@0 | 20 | if (observers.indexOf(observer) != -1) |
| michael@0 | 21 | return; |
| michael@0 | 22 | observers.unshift(observer); |
| michael@0 | 23 | }; |
| michael@0 | 24 | |
| michael@0 | 25 | var ensure = exports.ensure = function ensure(obj, destructorName) { |
| michael@0 | 26 | if (!destructorName) |
| michael@0 | 27 | destructorName = "unload"; |
| michael@0 | 28 | if (!(destructorName in obj)) |
| michael@0 | 29 | throw new Error("object has no '" + destructorName + "' property"); |
| michael@0 | 30 | |
| michael@0 | 31 | let called = false; |
| michael@0 | 32 | let originalDestructor = obj[destructorName]; |
| michael@0 | 33 | |
| michael@0 | 34 | function unloadWrapper(reason) { |
| michael@0 | 35 | if (!called) { |
| michael@0 | 36 | called = true; |
| michael@0 | 37 | let index = unloaders.indexOf(unloadWrapper); |
| michael@0 | 38 | if (index == -1) |
| michael@0 | 39 | throw new Error("internal error: unloader not found"); |
| michael@0 | 40 | unloaders.splice(index, 1); |
| michael@0 | 41 | originalDestructor.call(obj, reason); |
| michael@0 | 42 | originalDestructor = null; |
| michael@0 | 43 | destructorName = null; |
| michael@0 | 44 | obj = null; |
| michael@0 | 45 | } |
| michael@0 | 46 | }; |
| michael@0 | 47 | |
| michael@0 | 48 | // TODO: Find out why the order is inverted here. It seems that |
| michael@0 | 49 | // it may be causing issues! |
| michael@0 | 50 | unloaders.push(unloadWrapper); |
| michael@0 | 51 | |
| michael@0 | 52 | obj[destructorName] = unloadWrapper; |
| michael@0 | 53 | }; |
| michael@0 | 54 | |
| michael@0 | 55 | function unload(reason) { |
| michael@0 | 56 | observers.forEach(function(observer) { |
| michael@0 | 57 | try { |
| michael@0 | 58 | observer(reason); |
| michael@0 | 59 | } |
| michael@0 | 60 | catch (error) { |
| michael@0 | 61 | console.exception(error); |
| michael@0 | 62 | } |
| michael@0 | 63 | }); |
| michael@0 | 64 | } |
| michael@0 | 65 | |
| michael@0 | 66 | when(function(reason) { |
| michael@0 | 67 | unloaders.slice().forEach(function(unloadWrapper) { |
| michael@0 | 68 | unloadWrapper(reason); |
| michael@0 | 69 | }); |
| michael@0 | 70 | }); |
| michael@0 | 71 | |
| michael@0 | 72 | on('sdk:loader:destroy', function onunload({ subject, data: reason }) { |
| michael@0 | 73 | // If this loader is unload then `subject.wrappedJSObject` will be |
| michael@0 | 74 | // `destructor`. |
| michael@0 | 75 | if (subject.wrappedJSObject === unloadSubject) { |
| michael@0 | 76 | off('sdk:loader:destroy', onunload); |
| michael@0 | 77 | unload(reason); |
| michael@0 | 78 | } |
| michael@0 | 79 | // Note that we use strong reference to listener here to make sure it's not |
| michael@0 | 80 | // GC-ed, which may happen otherwise since nothing keeps reference to `onunolad` |
| michael@0 | 81 | // function. |
| michael@0 | 82 | }, true); |
